On an expensive guitar, you would want to leave any kind of setup and maintenance work to a professional, save changing the strings.
As long as the guitar is functional, it sounds like it needs some basic setup work and maintenance. The potentiometers that control the volume and tone get scratchy, and sticky over time. They can be cleaned with electronics cleaner, which usually will bring them back to working condition. Occasionally the capacitors go bad, and need to be replaced. Vintage style capacitors are available that look very close to the original.
You basically want to leave everything completely original, unless there is no other way to get it working. If you do get replacement parts, make sure that they are the correct part that would have been installed from the factory. Collectors are very picky, and can tell when something is not original. Also if you replace any parts, be sure to keep the originals, as they are not replaceable.
A professional luthier that specializes in vintage electric guitars would be the best person to bring it to. Make sure you find someone with a good reputation. They would be able to do all the setup, just like it was from the factory, or better. There are certain operations that only an experienced luthier can perform such as neck resets, refretting, etc.